Conventional flat battery in which a plurality of positive and negative electrodes are alternately superposed with separator layers therebetween, has been constructed in such a manner that two electrodes having a same polarity are connected to each other by a current collector member in the shape of a pair of glasses, and one of the pair of negative electrodes is superposed on one of the pair of positive electrodes with a separator layer therebetween and the other one of the pair of positive electrodes is then turned to be superposed on said one of the pair of negative electrodes with a separator layer therebetween and the other one of the pair of negative electrodes is then turned to be superposed on said other one of the pair of positive electrodes with a separator layer therebetween.
Therefore, there has been a possibility of internal short-circuit due to positional shifting of the electrodes or separator layers during the assembling, thereby to require a highly accurate assembling work. In addition, the assembling itself has been extremely complicated.